Printing apparatus, program, and printing method

ABSTRACT

A print start position is set to an appropriate position, and the time required for printing is shortened. A printing apparatus, which forms a row of dots from a print start position in a scanning direction to print on a medium to be printed, is provided with a sensor that is capable of detecting an edge, in the scanning direction, of the medium to be printed. The printing apparatus stores the result of detecting the edge of another medium to be printed, and, when printing on the medium to be printed, it reads out the stored detection result and determines the print start position based on that detection result.

TECHNICAL FIELD

The present invention relates to printing apparatuses and printingmethods for printing onto a medium to be printed, such as paper. Thepresent invention also relates to programs for controlling such printingapparatuses.

BACKGROUND ART

Inkjet printers that perform printing by intermittently ejecting ink areknown as printing apparatuses for printing images onto various types ofmedia to be printed, including paper, cloth, and film. In such inkjetprinters, printing is carried out by alternately repeating a process ofmoving the paper in the carrying direction and positioning it, and aprocess of ejecting ink from nozzles while moving the nozzles in thescanning direction.

In such inkjet printers, the paper is moved in the carrying directionwhile the edges of the paper are guided by guides. However, since theremay be manufacturing errors in the position at which the guides areprovided, there are individual differences for every printer. Therefore,there has been a possibility that the print start position will differfor each printer.

Accordingly, it has been suggested to provide a paper width sensor onthe printer and determine the print start position in accordance withthe result that is output by this paper width sensor.

In this case, the paper width sensor may be mounted on a carriage formoving the nozzles. The printer detects both edges of the paper with thepaper width sensor before printing, and determines the print startposition in accordance with the results of detecting both edges.

However, in such a method, it is necessary to move the carriage in thescanning direction and detect both edges of the paper before printing.That is to say, before printing, an operation to move the carriage isnecessary and thus the time required for printing becomes lengthened.

It is an object of the present invention to set the print start positionto an appropriate position, as well as shorten the time required forprinting.

DISCLOSURE OF INVENTION

The main aspect of the invention is a printing apparatus that forms arow of dots from a print start position in a scanning direction to printon a medium to be printed, comprising: a sensor that is capable ofdetecting an edge, in the scanning direction, of the medium to beprinted, wherein the print start position is determined based on aresult of detecting the edge of another medium to be printed.

Other features of the present invention will become clear through thepresent specification and the description in the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory diagram of an overall configuration of aninkjet printer of the present embodiment.

FIG. 2 is a diagram that schematically shows an area around a carriageof the inkjet printer of the present embodiment.

FIG. 3 is an explanatory diagram of an area around a carrying unit ofthe inkjet printer of the present embodiment.

FIG. 4 is a perspective view of the area around the carrying unit of theinkjet printer of the present embodiment.

FIG. 5 is an explanatory diagram showing the configuration of a linearencoder.

FIG. 6A is a timing chart of waveforms of output signals when the CRmotor 42 is rotating forward.

FIG. 6B is a timing chart of waveforms of output signals when the CRmotor 42 is rotating in reverse.

FIG. 7 is an explanatory diagram showing the arrangement of the nozzles.

FIG. 8 is an explanatory diagram of a paper width sensor.

FIG. 9 is an explanatory diagram showing the paper width sensormeasuring at a plurality of locations in the scanning direction.

FIG. 10 is a perspective view of the entire printer and a guide unit.

FIG. 11 is a diagram for explaining a print start position.

FIG. 12A is an explanatory diagram of when a printing region is shiftedto the right side of a piece of paper S.

FIG. 12B is an explanatory diagram of when the printing region isshifted to the left side of the paper S.

FIG. 13 is a flowchart of a calibration operation.

FIG. 14 is a flowchart of a printing operation.

FIG. 15 is an explanatory drawing showing the external structure of acomputer system.

FIG. 16 is a block diagram showing the configuration of the computersystem shown in FIG. 15.

FIG. 17 is an explanatory diagram showing a user interface.

FIG. 18 is an explanatory diagram of a format of print data.

A legend of the main reference numerals used in the drawings is shownbelow.

10 paper carrying unit, 11A paper insert opening, 11B roll paper insertopening, 13 paper supply roller, 14 platen, 15 paper feed motor (PFmotor), 16 paper feed motor driver (PF motor driver), 17A paper feedroller, 17B paper discharge rollers, 18A and 18B free rollers, 20 inkejection unit, 21 head, 22 head driver, 30 cleaning unit, 31 pumpdevice, 32 pump motor, 33 pump motor driver, 35 capping device, 40carriage unit, 41 carriage, 42 carriage motor (CR motor), 43 carriagemotor driver (CR motor driver), 44 pulley, 45 timing belt, 46 guiderail, 50 measuring instrument group, 51 linear encoder, 511 linearscale, 512 detecting section, 512A light emitting diode, 512B collimatorlens, 512C detection processing section, 512D photodiodes, 512E signalprocessing circuit, 512F comparators, 52 rotary encoder, 53 paperdetection sensor, 54 paper width sensor, 60 control unit, 61 CPU, 62timer, 63 interface section, 64 ASIC, 65 memory, 66 DC controller, 67host computer, 80 guide unit, 81 fixed guide, 82 movable guide

BEST MODE FOR CARRYING OUT THE INVENTION

At least the following matters will be made clear by the presentspecification and the description of the accompanying drawings.

A printing apparatus that forms a row of dots from a print startposition in a scanning direction to print on a medium to be printed,comprises: a sensor that is capable of detecting an edge, in thescanning direction, of the medium to be printed, wherein the print startposition is determined based on a result of detecting the edge ofanother medium to be printed. With such a printing apparatus, it ispossible to provide the print start position at an appropriate position,as well as to shorten the time required for printing.

In the printing apparatus, it is desirable that the result of detectingthe edge of the other medium to be printed is stored; and that whenprinting on the medium to be printed, the stored detection result isread out, and the print start position is determined based on thatdetection result. With such a printing apparatus, the print startposition is determined based on stored information, and thus it is notnecessary to detect the edge every time printing is performed, and timerequired for printing can be shortened.

In the printing apparatus, it is desirable that the sensor is providedon a carriage that is movable in the scanning direction. It is alsopreferable that the print start position is determined based oninformation about a position of the carriage for when the sensordetected the edge of the other medium to be printed. It is alsopreferable that the position of the carriage is detected using anencoder. With such a printing apparatus, it is possible to detect theposition of the edge of the medium to be printed based on the positionof the carriage.

In the printing apparatus, it is desirable that the information aboutthe position of the carriage for when the sensor detected the edge ofthe other medium to be printed is stored; that when printing on themedium to be printed, the information about the position of the carriagethat has been stored is read out; and that the print start position isdetermined based on the information about the position of the carriagethat has been read out. With such a printing apparatus, the print startposition is determined based on the stored carriage position, and thusit is not necessary to detect the position of the edge every timeprinting is performed, and time required for printing can be shortened.

In the printing apparatus, it is desirable that information about arelative positional relationship between the edge of the medium to beprinted and the print start position is obtained; and that the printstart position is determined based on this information and the result ofdetecting the edge. Furthermore, it is preferable that the informationabout the relative positional relationship between the edge of themedium to be printed and the print start position is information about ablank space that is to be formed on the medium to be printed.

In the printing apparatus, it is desirable that information about themedium to be printed is obtained; and that the print start position isdetermined based on the information about the medium to be printed andthe result of detecting the edge. It is also preferable that theinformation about the medium to be printed is information about a widthof the medium to be printed.

Furthermore, in the printing apparatus, it is preferable that printingis carried out on an entire surface of the medium to be printed; andthat the print start position is a position in the scanning directionthat is outside of or on the edge of the medium to be printed.

With such a printing apparatus, when performing so-called borderlessprinting, it is possible to provide the print start position at anappropriate position as well as to shorten the time required forprinting.

A printing apparatus that forms a row of dots from a print startposition in a scanning direction to print on a medium to be printed,comprises: a sensor that is capable of detecting an edge, in thescanning direction, of the medium to be printed; wherein the sensor isprovided on a carriage that is movable in the scanning direction;wherein a position of the carriage is detected using an encoder; whereininformation about the position of the carriage for when the edge of theother medium to be printed was detected is stored; wherein at least oneof information about a width of the medium to be printed and informationabout a blank space that is to be formed on the medium to be printed isobtained; wherein when printing on the medium to be printed, theinformation about the position of the carriage is read out; and whereinthe print start position is determined based on the information aboutthe position of the carriage, and at least one of the information aboutthe width of the medium to be printed and the information about theblank space that is to be formed on the medium to be printed. With sucha printing apparatus, it is possible to provide the print start positionat an appropriate position as well as to shorten the time required forprinting.

Furthermore, a program causes a printing apparatus that forms a row ofdots from a print start position in a scanning direction to print on amedium to be printed, to achieve: a function of detecting an edge, inthe scanning direction, of the medium to be printed; and a function ofdetermining the print start position based on a result of detecting theedge of another medium to be printed. With such a program, it ispossible to control the printing apparatus such that it provides theprint start position at an appropriate position, as well as shortens thetime required for printing.

Furthermore, it is also possible to provide a computer-readable storagemedium containing codes for causing a printing apparatus that forms arow of dots from a print start position in a scanning direction to printon a medium to be printed, to achieve: a function of detecting an edge,in the scanning direction, of the medium to be printed; and a functionof determining the print start position based on a result of detectingthe edge of another medium to be printed.

Furthermore, a printing method for printing on a medium to be printed,comprises: a step of detecting an edge, in a scanning direction, ofanother medium to be printed; a step of determining a print startposition based on a result of detecting the edge of the other medium tobe printed; and a step of ejecting ink droplets, in the scanningdirection, from the determined print start position to print on a mediumto be printed that is different from the other medium to be printed.

Furthermore, a computer system comprises a main computer unit and aprinting apparatus, forms a row of dots from a print start position in ascanning direction to print on a medium to be printed, and is providedwith a sensor that is capable of detecting an edge, in the scanningdirection, of the medium to be printed, wherein the print start positionis determined based on a result of detecting the edge of another mediumto be printed. With such a computer system, it is possible to providethe print start position at an appropriate position, as well as toshorten the time required for printing.

===Overview of Printing Apparatus (Inkjet Printer)===

<Regarding the Configuration of the Inkjet Printer>

An overview of an inkjet printer serving as an example of a printingapparatus is described with reference to FIG. 1, FIG. 2, FIG. 3, andFIG. 4. It should be noted that FIG. 1 is an explanatory diagram of theoverall configuration of an inkjet printer of the present embodiment.FIG. 2 is a schematic diagram of an area around the carriage of theinkjet printer of the present embodiment. FIG. 3 is an explanatorydiagram of an area around the carrying unit of the inkjet printer of thepresent embodiment. FIG. 4 is a perspective view of an area around thecarrying unit of the inkjet printer of the present embodiment.

The inkjet printer of the present embodiment has a paper carrying unit10, an ink ejection unit 20, a cleaning unit 30, a carriage unit 40, ameasuring instrument group 50, and a control unit 60.

The paper carrying unit 10 is for feeding paper, which is an example ofa medium to be printed, into a printable position and making the papermove in a predetermined direction (the direction perpendicular to thepaper face in FIG. 1 (hereinafter, this is referred to as the papercarrying direction)) by a predetermined movement amount during printing.In other words, the paper carrying unit 10 functions as a carryingmechanism for carrying paper. The paper carrying unit 10 has a paperinsert opening 11A and a roll paper insert opening 11B, a paper supplymotor (not shown), a paper supply roller 13, a platen 14, a paper feedmotor (hereinafter, referred to as “PF motor”) 15, a paper feed motordriver (hereinafter, referred to as “PF motor driver”) 16, a paper feedroller 17A and paper discharge rollers 17B, and free rollers 18A andfree rollers 18B. However, the paper carrying unit 10 does notnecessarily have to include all of these structural elements in order tofunction as a carrying mechanism.

The paper insert opening 11A is where paper, which is the medium to beprinted, is inserted. The roll paper insert opening 11B is where rollpaper is inserted. The paper supply motor (not shown) is a motor forcarrying the paper that has been inserted into the paper insert opening11A into the printer, and is constituted by a pulse motor. The papersupply roller 13 is a roller for automatically carrying the paper thathas been inserted into the paper insert opening 11A into the printer,and is driven by the paper supply motor 12. The paper supply roller 13has a transverse cross-sectional shape that is substantially the shapeof the letter D. The peripheral length of a circumference section of thepaper supply roller 13 is set longer than the carrying distance to thePF motor 15, so that using this circumference section the medium to beprinted can be carried up to the PF motor 15. It should be noted that aplurality of media to be printed are kept from being supplied at onetime by the rotational drive force of the paper supply roller 13 and thefrictional resistance of separating pads (not shown). The sequencethrough which the medium to be printed is carried is described in detaillater.

The platen 14 supports the paper S during printing. The PF motor 15 is amotor for feeding paper, which is an example of a medium to be printed,in the paper carrying direction, and is constituted by a DC motor. ThePF motor driver 16 is for driving the PF motor 15. The paper feed roller17A is a roller for feeding the paper S that has been carried into theprinter by the paper supply roller 13 to a printable region, and isdriven by the PF motor 15. The free rollers 18A are provided in aposition that is in opposition to the paper feed roller 17A, and pushthe paper S toward the paper feed roller 17A by sandwiching the paper Sbetween them and the paper feed roller 17A.

The paper discharge rollers 17B are rollers for discharging the paper Sfor which printing has finished to outside the printer. The paperdischarge rollers 17B are driven by the PF motor 15 through a gear wheelthat is not shown in the drawings. The free rollers 18B are provided ina position that is in opposition to the paper discharge rollers 17B, andpush the paper S toward the paper discharge rollers 17B by sandwichingthe paper S between them and the paper discharge rollers 17B.

The ink ejection unit 20 is for ejecting ink onto paper, which is anexample of the medium to be printed. The ink ejection unit 20 has a head21 and a head driver 22. The head 21 has a plurality of nozzles, whichare ink ejection sections, and ejects ink intermittently from each ofthe nozzles. The head driver 22 is for driving the head 21 so that inkis ejected intermittently from the head.

The cleaning unit 30 is for preventing the nozzles of the head 21 frombecoming clogged. The cleaning unit 30 has a pump device 31 and acapping device 35. The pump device is for extracting ink from thenozzles in order to prevent the nozzles of the head 21 from becomingclogged, and has a pump motor 32 and a pump motor driver 33. The pumpmotor 32 sucks out ink from the nozzles of the head 21. The pump motordriver 33 drives the pump motor 32. The capping device 35 is for sealingthe nozzles of the head 21 when printing is not being performed (duringstandby) so that the nozzles of the head 21 are kept from clogging.

The carriage unit 40 is for making the head 21 scan and move in apredetermined direction (in FIG. 1, the left and right direction of thepaper face (hereinafter, this is referred to as the scanningdirection)). The carriage unit 40 has a carriage 41, a carriage motor(hereinafter, referred to as CR motor) 42, a carriage motor driver(hereinafter, referred to as CR motor driver) 43, a pulley 44, a timingbelt 45, and a guide rail 46. The carriage 41 is movable in the scanningdirection, and the head 21 is fastened to it (thus, the nozzles of thehead 21 intermittently eject ink as they are moved in the scanningdirection). The carriage 41 also removably holds ink cartridges 48 thatcontain ink. The CR motor 42 is a motor for moving the carriage in thescanning direction, and is constituted by a DC motor. The CR motordriver 43 is for driving the CR motor 42. The pulley 44 is attached tothe rotation shaft of the CR motor 42. The timing belt 45 is driven bythe pulley 44. The guide rail 46 is for guiding the carriage 41 in thescanning direction.

The measuring instrument group 50 includes a linear encoder 51, a rotaryencoder 52, a paper detection sensor 53, and a paper width sensor 54.The linear encoder 51 is for detecting the position of the carriage 41.The rotary encoder 52 is for detecting the amount of rotation of thepaper feed roller 17A. It should be noted that the configuration, forexample, of the encoders is discussed later. The paper detection sensor53 is for detecting the position of the front end of the paper to beprinted. The paper detection sensor 53 is provided in a position whereit can detect the position of the front end of the paper as the paper isbeing carried toward the paper feed roller 17A by the paper supplyroller 13. It should be noted that the paper detection sensor 53 is amechanical sensor that detects the front end of the paper through amechanical mechanism. More specifically, the paper detection sensor 53has a lever that can be rotated in the paper carrying direction, andthis lever is arranged so that it protrudes into the path over which thepaper is carried. In this way, the front end of the paper comes intocontact with the lever and the lever is rotated, and thus the paperdetection sensor 53 detects the position of the front end of the paperby detecting the movement of the lever. The paper width sensor 54 isattached to the carriage 41. The paper width sensor 54 is an opticalsensor having a light-emitting section 541 and a light-receiving section543, and detects whether the paper is present or not at the position ofthe paper width sensor 54 by detecting light that is reflected by thepaper. The paper width sensor 54 detects the positions of the edges ofthe paper while being moved by the carriage 41, so as to detect thewidth of the paper. The paper width sensor 54 can detect the front endof the paper according to the position of the carriage 41. The paperwidth sensor 54 is an optical sensor, and thus detects positions withhigher precision than the paper detection sensor 53.

The control unit 60 is for carrying out control of the printer. Thecontrol unit 60 has a CPU 61, a timer 62, an interface section 63, anASIC 64, a memory 65, and a DC controller 66. The CPU 61 is for carryingout the overall control of the printer, and sends control commands tothe DC controller 66, the PF motor driver 16, the CR motor driver 43,the pump motor driver 32, and the head driver 22. The timer 62periodically generates interrupt signals with respect to the CPU 61. Theinterface section 63 exchanges data with a host computer 67 providedoutside the printer. The ASIC 64 controls the print resolution and thedrive waveforms of the head, for example, based on print informationsent from the host computer 67 through the interface section 63. Thememory 65 is for reserving an area for storing the programs for the ASIC64 and the CPU 61 and a work area, for instance, and has storage meanssuch as a RAM or an EEPROM. The DC controller 66 controls the PF motordriver 16 and the CR motor driver 43 based on control commands sent fromthe CPU 61 and the output from the measuring instrument group 50.

<Regarding the Configuration of the Encoders>

FIG. 5 is an explanatory diagram of the linear encoder 51.

The linear encoder 51 is for detecting the position of the carriage 41,and has a linear scale 511 and a detecting section 512.

The linear scale 511 is provided with slits at a predetermined spacing(for example, every 1/180 inch (1 inch equals 2.54 cm)), and is fastenedto the body of the printer.

The detecting section 512 is provided in opposition to the linear scale511, and is on the carriage 41 side. The detecting section 512 has alight-emitting diode 512A, a collimator lens 512B, and a detectionprocessing section 512C. The detection processing section 512C isprovided with a plurality (for instance, four) photodiodes 512D, asignal processing circuit 512E, and two comparators 512Fa and 512Fb.

The light-emitting diode 512A emits light when a voltage Vcc is appliedto it via resistors on both sides, and this light is incident on thecollimator lens. The collimator lens 512B turns the light that isemitted from the light-emitting diode 512A into parallel light, andirradiates the parallel light on the linear scale 511. The parallellight that passes through the slits provided in the linear scale thenpasses through stationary slits (not shown) and is incident on thephotodiodes 512D. The photodiodes 512D convert the incident light intoelectric signals. The electric signals that are output from thephotodiodes are compared in the comparators 512Fa and 512Fb, and theresults of these comparisons are output as pulses. Then, the pulse ENC-Aand the pulse ENC-B that are output from the comparators 512Fa and 512Fbbecome the output of the linear encoder 51.

FIG. 6A and FIG. 6B are timing charts showing two types of output signalwaveforms of the linear encoder 51, and more specifically, FIG. 6A is atiming chart of the output signal waveform when the CR motor 42 isrotating forward, and FIG. 6B is a timing chart of the output signalwhen the CR motor 42 is rotating in reverse.

As shown in FIG. 6A and FIG. 6B, the phases of the pulse ENC-A and thepulse ENC-B are misaligned by 90 degrees both when the CR motor 42 isrotating forward and when it is rotating in reverse. When the CR motor42 is rotating forward, that is, when the carriage 41 is moving in themain-scanning direction, then, as shown in FIG. 6A, the phase of thepulse ENC-A leads the phase of the pulse ENC-B by 90 degrees. On theother hand, when the CR motor 42 is rotating in reverse, then, as shownin FIG. 6B, the phase of the pulse ENC-A trails the phase of the pulseENC-B by 90 degrees. A single period T of the pulses is equivalent tothe time during which the carriage 41 is moved by the spacing of a slitin the linear scale 511 (for example, by 1/180 inch (1 inch equals 2.54cm)).

The position of the carriage 41 is detected as follows. First, therising edge or the falling edge of either the pulse ENC-A or ENC-B isdetected, and the number of detected edges is counted. The position ofthe carriage 41 is calculated based on the counted number. As regardsthe counted number, when the CR motor 42 is rotating forward, a “+1” isadded for each detected edge, and when the CR motor 42 is rotating inreverse, a “−1” is added for each detected edge. Since the period of thepulses ENC is equal to the slit spacing of the linear scale 511, theamount that the carriage 41 has moved from a position where the countnumber is “0” can be found by multiplying the counted number by the slitspacing. In other words, the resolution of the linear encoder 51 in thiscase is the slit spacing of the linear scale 511. It is also possible todetect the position of the carriage 41 using both the pulse ENC-A andthe pulse ENC-B. The periods of the pulse ENC-A and the pulse ENC-B areequal to the slit spacing of the linear scale 511, and the phases of thepulses ENC-A and ENC-B are misaligned by 90 degrees, so that if therising edges and the falling edges of the pulses are detected and thenumber of detected edges is counted, then a counted number of “1”corresponds to ¼ of the slit spacing of the linear scale 511. Therefore,by multiplying the counted number by ¼ of the slit spacing, the amountthat the carriage 41 has moved from a position where the count number is“0” can be found. That is, the resolution of the linear encoder 51 inthis case is ¼ the slit spacing of the linear scale 511.

The velocity Vc of the carriage 41 is detected as follows. First, therising edges or the falling edges of either the pulse ENC-A or ENC-B aredetected. The time interval between edges of the pulses is counted witha timer counter. The period T (T=T1, T2, . . . ) is obtained from thevalue that is counted. If λ (lambda) is the slit spacing of the linearscale 511, then the velocity of the carriage can be sequentiallyobtained as λ/T. It is also possible to detect the velocity of thecarriage 41 using both the pulse ENC-A and the pulse ENC-B. By detectingthe rising edges and the falling edges of the pulses, the time intervalbetween edges, which corresponds to ¼ of the slit spacing of the linearscale 511, is counted by the timer counter. The period T (T=T1, T2, . .. ) is obtained from the value that is counted. If λ is the slit spacingof the linear scale 511 then the velocity Vc of the carriage can befound sequentially as Vc=λ/(4T).

It should be noted that the rotary encoder 52 has substantially the sameconfiguration as the linear encoder 51, except that a rotation disk 521that rotates in accordance with rotation of the paper feed roller 17A isused in place of the linear scale 511 that is provided on the body ofthe printer, and that a detecting section 522 that is provided on thebody of the printer is used in place of the detecting section 512 thatis provided on the carriage 41 (see FIG. 4).

It should be noted that what the rotary encoder 52 directly detects isthe rotation amount of the paper feed roller 17A, and it is not thecarry amount of the paper. When the paper feed roller 17A is rotated tocarry the paper, a carry error occurs due to slippage between the paperfeed roller 17A and the paper. Consequently, the rotary encoder 52cannot directly detect the carry error of the carry amount of the paper.Accordingly, a table that expresses the relationship between therotation amount detected by the rotary encoder 52 and the carry error iscreated and stored in the memory 65 of the control unit 60. Then, thetable is referenced based on the results detected by the rotary encoder,and the carry error is thereby detected. This table is not limited toexpressing the relationship between the rotation amount and the carryerror, and may also be a table that expresses the relationship betweenthe number of times of carries, for example, and the carry error. Also,because slippage differs depending on the characteristics of the paper,it is also possible to create a plurality of tables corresponding to thepaper characteristics and to store these in the memory 65.

<Regarding the Configuration of the Nozzles>

FIG. 7 is an explanatory diagram showing the arrangement of the nozzlesin the lower surface of the head 21. In the lower surface of the head 21there are formed a dark black ink nozzle group KD, a light black inknozzle group KL, a dark cyan ink nozzle group CD, a light cyan inknozzle group CL, a dark magenta ink nozzle group MD, a light magentanozzle group ML, and a yellow ink nozzle group YD. Each nozzle group isprovided with a plurality (in the present embodiment, n pieces) ofnozzles, which are ejection openings for ejecting the respective colorsof ink. It should be noted that the first alphabet letter in thereference characters indicating the nozzle groups represents the inkcolor, whereas the accompanying letter “D” means that the ink has arelatively high darkness and the accompanying letter “L” means that theink has a relatively low darkness.

The plurality of nozzles of the nozzle groups are arranged at a constantspacing (nozzle pitch: k·D) in the paper carrying direction. Here, D isthe minimum dot pitch in the paper carrying direction (that is, thespacing at the highest resolution of the dots formed on the paper S).Also, k is an integer of 1 or more.

The nozzles of the nozzle groups are assigned numbers that becomesmaller toward the downstream side (#1 to #n). Also, as regards theirpositions in the paper carrying direction, the nozzles of each nozzlegroup are provided so that they are positioned between the nozzles ofadjacent nozzle groups. For example, the first nozzle #1 of the lightblack ink nozzle group KL is provided between the first nozzle #1 andthe second nozzle #2 of the dark black ink nozzle group KD, as regardsits position in the paper carrying direction. Further, the paper widthsensor 54 is provided substantially in the same position as the n-thnozzle #n furthest downstream, as regards its position in the papercarrying direction. Each nozzle is provided with a piezo element (notshown) as a drive element for driving the nozzle and making it eject inkdroplets.

During printing, the paper S is carried intermittently by the papercarrying unit 10 by a predetermined carry amount, and between theseintermittent carries, the carriage 41 is moved in the main-scanningdirection and ink droplets are ejected from the nozzles.

===Detecting the Edges of the Paper===

In the present embodiment, the paper width sensor 54 detects thedistance PG to the paper, and depending on the distance PG, detects thepresence or absence of paper in the detection position. Then, bydetecting the presence or absence of paper in the scanning direction,the paper width sensor 54 detects both edges of the paper to detect thewidth of the paper.

FIG. 8 is an explanatory diagram of the paper width sensor 54 thatdetects the distance PG. It should be noted that as can be seen from thefigure, the paper width sensor 54 functions as a gap sensor.

In the figure, the paper width sensor 54 has a light-emitting section541 and two light-receiving sections (a first light-receiving section543A and a second light-receiving section 543B). The light-emittingsection 541 contains a light emitting diode, and irradiates light ontothe paper S, which is the medium to be printed. The firstlight-receiving section 543A has a light-receiving element that outputsan electric signal that depends on the amount of light received. Thesecond light-receiving section 543B has a light-receiving element, likethe first light-receiving section 543A. The second light receivingelement 543B is provided in a position further from the light-emittingsection compared to the first light-receiving section 543A.

The light that is emitted from the light-emitting section 541 isincident on the paper S. The light that is incident on the paper S isreflected by the paper. The light that is reflected by the paper S isincident on the light-receiving elements. The light that is incident onthe light-receiving elements is converted by the light-receivingelements to electric signals that depend on the amount of light that isincident.

If the paper S is on the platen 14, then the distance PG is small.Consequently, the light that is reflected by the paper S is principallyincident on the first light-receiving section 543A, and only diffusedlight is incident on the second light-receiving section 543B.Consequently, the output signal of the first light-receiving section543A becomes larger than the output signal from the secondlight-receiving section 543B.

On the other hand, when the paper S is not on the platen 14, thedistance PG is large. Consequently, the light that is reflected by theplaten is principally incident on the second light-receiving section543B, and only diffused light is incident on the first light-receivingsection 543A. Consequently, the output signal of the secondlight-receiving section 543B becomes larger than the output signal fromthe first light-receiving section 543A.

Consequently, if the relationship between the output signal ratios ofthe two light-receiving sections and the distance PG (or the presence orabsence of paper) is determined in advance, then based on the ratio ofthe output signals of the light-receiving sections, it is possible todetect the presence or absence of paper at the detection position. Inthis case, information about the relationship between the ratio of theoutput signals of light-receiving sections and the distance PG (or thepresence or absence of paper) can be stored in the memory 65 as a table.

FIG. 9 is an explanatory diagram showing the paper width sensor 54measuring the distance PG at a plurality of locations in the scanningdirection. In the figure, identical structural components have beenassigned same reference numerals, and thus description thereof isomitted.

In the figure, the paper width sensor 54 is provided on the carriage 41.Consequently, the paper width sensor 54 is capable of moving in thescanning direction when the carriage moves. Thus the paper width sensor54 can detect the distance PG at a plurality of locations in thescanning direction.

On the other hand, the position of the carriage 41 in the scanningdirection can be detected by the linear encoder 51 as noted above. Thatis to say, the position at which the distance PG is measured by thepaper width sensor 54 is detected by the linear encoder 51.

Thus, by detecting the position of the carriage for when the distancePG, which is detected by the paper width sensor 54, changes, it ispossible to detect the edge of the paper. It should be noted that bydetecting both edges of the paper, it is possible to detect the width ofthe paper.

===Guide Unit===

FIG. 10 is a perspective view showing the overall printer and a guideunit.

In addition to the structural elements noted above, the printer 1 has ahousing 3, an upper lid 5, an operation section 7 and a display section9. The housing 3 is a box containing the above noted structural elements(for example, elements such as the paper carrying unit 10, the inkejection unit 20, the cleaning unit 30, the carriage unit 40, themeasuring instrument group 50 and the control unit 60 and the like). Theupper lid 5 is a lid that is capable of rotating in an open/closedirection about a rotation shaft (not shown) provided on the housing 3.When the upper lid 5 is opened, the paper carrying unit 10 and thecarriage unit 40, for example, that are contained in the housing 3 canbe seen. The upper lid 5 is opened and closed at times such as whenchanging a cartridge or when the paper is jammed, for example. Theoperation section 7 is provided on the housing 3, and has buttons. Byoperating the buttons, the user can perform various settings of theprinter 1. The display section 9 is provided on the housing 3, and haslamps. It is possible to, for example, confirm the operations of theprinter 1 in accordance with flashing of the lamps. It should be notedthat the display section 9 may also be a liquid crystal display panelinstead of lamps.

A guide unit 80 is arranged to support the posture of the paper when thepaper S is supplied into the printer from the paper insert opening 11A.The guide unit 80 is provided with a fixed guide 81 and a movable guide82. The fixed guide 81 is mounted integrally with the body of theprinter, and has a guide face that is perpendicular to the scanningdirection. When the paper S is supplied from the paper insert opening11A, the fixed guide 81 contacts the side edge of the paper with theguide face, and when the paper is carried, it guides the paper S in thecarrying direction. The movable guide 82 is provided such that it iscapable of moving in the scanning direction with respect to the body ofthe printer, and has a guide face that is perpendicular to the scanningdirection. It is possible to change the position of the movable guide 82in the scanning direction so as to be able to set paper of varioussizes. One edge of the paper is made to contact the fixed guide, and theother edge of the paper is made to contact the movable guide 82. Byconfining the edges of the paper with the fixed guide and the movableguide, it is possible to suppress skewing of the paper when the paper isbeing supplied.

===Determining the Print Staff Position===

<Regarding the Print Start Position>

FIG. 11 is a diagram for describing the print staff position. In thisfigure, structural elements that have already been described areassigned identical reference numerals, and thus description thereof isomitted. It should be noted that in the figure, the edges of the paper Sare confined by the fixed guide 81 and the movable guide 82, and thepaper is supplied while skewing is suppressed.

In the figure, “standby position” is the position at which the carriage41 waits when it is not printing, and is referred to as the so-called“home position”. The capping device 35 is provided in the vicinity ofthis position. When the carriage 41 is in the standby position when itis not printing, the capping device 35 seals the nozzles of the head 21and prevents the nozzles from clogging. Then, when the carriage 41 thatis in the standby position receives a print command, it starts to movein the scanning direction toward the printing region.

A “printable position” is a position at which the nozzles of the head 21are capable of ejecting ink. However, if, for example, the nozzles startejecting ink when the carriage 41 is at the printable position, then theink will land on the platen 14 and soil the platen because there is nopaper below the nozzles. If the carriage 41 moves in the scanningdirection when the carriage 41 is at the printable position, then pulsesignals are output from the linear encoder 51. Consequently, when thecarriage 41 is on the printing region side of the printable position (inthe figure, the side to the left of the printable position), the controlunit 60 can detect the amount that the carriage has moved from theprintable position, based on the output signal of the linear encoder 51.It should be noted that when the carriage moves a predetermined amountin the scanning direction, a pulse signal is output from the linearencoder 51, and thus the control unit 60 is able to detect the positionof the carriage 41 in the scanning direction in accordance with thecount of the pulse signals from the linear encoder 51.

A “print start position” is a position at which the nozzles of the head21 start to eject ink, and is a position that can be changed dependingon the print mode. The figure shows a method in which printing isperformed leaving 3 mm of blank space from the edge of the paper S. Theprint start position is determined by counting the pulse signals outputfrom the linear encoder 51. In the figure, the number of pulses thatcorrespond to a movement amount X from the printable position iscounted. It should be noted that the movement amount X is a value thatis set in each printer so as to give a predetermined amount of blankspace (3 mm) when printing. Setting of the movement amount X isdescribed below.

A “print end position” is a position at which the nozzles of the head 21stop ejecting ink, and is a position that can be changed depending onthe print mode. The figure shows a method in which printing is performedleaving 3 mm of blank space from the edge of the paper S. Consequently,the width of the region that is printed on the paper S is a value thatis 6 mm less than a width PW of the paper (PW—6 mm).

It is desirable that the region that is printed on the paper S has equalblank space on its lefi and right side. On the other hand, when printingis performed such that the paper width sensor 54 first detects thepositions of both edges of the paper and then determines equal blankspaces on the left and right, an operation for detecting the position ofboth edges of the paper becomes necessary, and thus, the print operationis delayed.

Thus, in the printer of the present embodiment, the result of detectingthe positions of both edges of the paper is not used when startingprinting, but rather, printing is started when the carriage is moved bya predetermined movement amount X from the printable position. Thus, theoperation of detecting the position of both edges of the paper whenstarting printing is not required, and thus it is possible to start theprinting operation at an earlier timing.

However, if the distance between the printable position and the printstart position is fixed for all printers, then as described below, ashift may occur in the printing position, and the blank space on theleft and right may become unequal.

For example, when the fixed guide 81 is mounted to the left of an idealmounting position because of a mounting error of the fixed guide, theprinting region will be shifted to the right side of the paper S asshown in FIG. 12A, and it is not possible to form equal blank space.Alternatively, if the printable position is positioned to the right sidedue to a mounting error of the linear encoder, then the printing regionwill also be shifted to the right side of the paper S.

Furthermore, for example, when the fixed guide 81 is mounted to theright of an ideal mounting position because of a mounting error of thefixed guide, the printing region will be shifted to the left side of thepaper S as shown in FIG. 12B, and it is not possible to form equal blankspace. Alternatively, if the printable position is positioned to theleft side due to a mounting error of the linear encoder, then theprinting region will also be shifted to the left side of the paper S.

Consequently, in order to position the printing region in the center ofthe paper S such that the blank space on the left and right becomesequal, it is necessary to alter the distance X between the printableposition and the print start position for each printer.

Thus, in the present embodiment, in order to determine the print startposition for each printer, a calibration operation is performedaccording to the sequence given below.

<Calibration Operation>

FIG. 13 is a flowchart of the calibration operation. The calibrationoperation is performed either before the printer is shipped from thefactory, or when the user instructs the printer to perform calibration.It should be noted that the calibration operation is controlled by thecontrol unit 60 of the printer.

First, the printer receives a calibration command (S101). This commandis sent to the printer in accordance with a signal from the maincomputer unit, or as a signal input from the operation section 7. Itshould be noted that at this time, the carriage 41 is usually in thestandby position.

Next, the CR motor is driven to move the carriage in the scanningdirection (S102). Then, the carriage 41 moves from the standby positionto the printable position.

When the carriage 41 arrives at the printable position, the linearencoder 51 starts to output pulse signals in accordance with themovement of the carriage, and thus the number of pulses is counted(S103). It should be noted that the number of pulses that are counted isinformation about the movement amount by which the carriage has movedfrom the printable position. After the carriage 41 passes the printableposition, it continues to move toward the printing region.

When the carriage moves further from the printable position, the paperwidth sensor 54 detects the edge of the paper (S104). That is to say, atfirst, the paper width sensor 54 outputs a signal indicating thepresence of the platen 14, but after this it outputs a signal indicatingthe presence of paper, and thus when the output signal changes, thatposition is detected as the position of the edge of the paper.

Lastly, the printer stores the value of the count for when the edge ofthe paper was detected in the EEPROM of the memory 65 as a correctionvalue (S105).

The correction value stored in the memory 65 is the number of pulsescorresponding to the distance from the printable position to the edge ofthe paper. This correction value is a value that differs for eachprinter depending on manufacturing errors of the printer.

For example, when the fixed guide 81 is mounted to the left side of anideal mounting position, the correction value becomes large.Furthermore, when the printable position is positioned to the right sidebecause of a mounting error of the linear encoder, the correction valueis also large.

Furthermore, for example, when the fixed guide 81 is mounted to theright side of an ideal mounting position, the correction value becomessmall. Furthermore, when the printable position is positioned to theleft side because of a mounting error of the linear encoder, thecorrection value is also small.

Thus, with the present embodiment, even if manufacturing errors arepresent in each printer, it is possible to set the print start positionin accordance with individual printer differences and to calibratemanufacturing errors.

Thus, as shown below, the printer of the present embodiment uses thiscorrection value to calculate the distance X from the printable positionto the print start position, and then prints on the paper.

<Printing Operation>

FIG. 14 is a flowchart of the printing operation. The printing operationdescribed here is the printing operation of the first pass. Here, “pass”refers to one scanning movement of the nozzles (or the carriage, or thehead) in the scanning direction. It should be noted that this printingoperation is controlled by the control unit 60 of the printer.

First, the printer receives a print command (S101). This print commandis triggered by a print signal that is transmitted from the maincomputer unit.

Next, the printer determines the width of the blank space formed on theleft and right of the paper (S102). The width of the blank space isusually half the value obtained by subtracting the width of the printingregion from the paper width. Here, the paper width can be determined byobtaining information about the printing paper. Furthermore, as regardsthe width of the printing region, information about the width of theprinting region is contained in the print signal transmitted from themain computer unit. It should be noted that when information about thewidth of the blank space is included in the print signal transmittedfrom the main computer unit, it is not necessary for the printer todetermine the width of the blank space.

Next, the printer calculates the number of pulses of the linear encoder51, which corresponds to the width of the blank space (S103). Forexample, if the width of the blank space is 3 mm and the linear encoder51 outputs one pulse signal every 0.141 mm, the number of pulses thatcorresponds to a blank-space width of 3 mm is approximately 21.

Next, the printer reads out the stored correction value (S204). Here,the “stored correction value” is the correction value that wasdetermined in the above-noted calibration operation. Thus, thiscorrection value, as noted above, is the number of pulses thatcorresponds to the distance from the printable position to the edge ofthe paper.

Next, the printer calculates the distance X from the printable positionto the print start position (S205). The distance X from the printableposition to the print start position may be the sum of adding thecorrection value and the number of pulses corresponding to the width ofthe blank space. That is to say, by calculating the distance X, theprint start position is determined.

Next, the printer drives the CR motor to move the carriage in thescanning direction (S206). Thus the carriage 41 moves from the standbyposition toward the print start position.

As the carriage 41 moves from the standby position toward the printstart position, the carriage 41 passes the printable position. Then,when the carriage 41 arrives at the printable position, the linearencoder 51 starts to output pulse signals in accordance with themovement of the carriage, and thus the number of pulses are counted(S207). It should be noted that the number of pulses corresponding tothe distance X (i.e., the number of pulses which is the sum of thecorrection value and the number of pulses corresponding to the width ofthe blank space) can be decremented every time a pulse signal is outputfrom the linear encoder 51.

When the number of counted pulses becomes the number of pulsescorresponding to the distance X, the carriage has reached the printstart position (S208). On this timing, the nozzles start to eject ink(S209). Thus, the print start position is set to a position that islocated away from the edge of the paper by the width of the blank spacethat has been set. Further, when the carriage arrives at the print endposition (S210), ejection of ink from the nozzles is ended. Thus, theprint end position is set to a position that is located away from theedge of the paper by the width of the blank space that has been set.That is to say, the width of the blank space on the left and right isarranged equally.

It should be noted that when printing the next pass, the sequence of theprinting operation is repeated in a similar manner. However, since thepaper width sensor 54 is capable of detecting the position of both edgesof the paper in the first pass, the print start position and the printend position in the second and subsequent passes may be determined basedon the positions of the edges that have been detected.

As described above, with the present embodiment, since it is notnecessary to detect both edges of the paper with the paper width sensor54 every time printing is performed, it is possible to shorten the timerequired for printing.

===Configuration of Computer System Etc.===

Next, an embodiment of a computer system, a computer program, and astorage medium storing the computer program are described with referenceto the drawings.

FIG. 15 is an explanatory drawing showing the external structure of thecomputer system. A computer system 1000 is provided with a main computerunit 1102, a display device 1104, a printer 1106, an input device 1108,and a reading device 1110. In this embodiment, the main computer unit1102 is accommodated within a mini-tower type housing; however, this isnot a limitation. A CRT (cathode ray tube), a plasma display, or aliquid crystal display device, for example, is generally used as thedisplay device 1104, but there is no limitation to this. The printer1106 is the printer described above. In this embodiment, the inputdevice 1108 is a keyboard 1108A and a mouse 1108B, but there is nolimitation to these. In this embodiment, a flexible disk drive device1110A and a CD-ROM drive device 1110B are used as the reading device1110, but it is not limited to these, and it may also be other types ofdevices such as a MO (magnet optical) disk drive device or a DVD(digital versatile disk), for example.

FIG. 16 is a block diagram showing the configuration of the computersystem shown in FIG. 15. An internal memory 1202 such as a RAM isprovided inside the housing accommodating the main computer unit 1102,and also an external memory such as a hard disk drive unit 1204 isprovided.

A computer program for controlling the operation of the above printercan be downloaded onto the computer 1000, for example, connected to theprinter 1106 via a communications line such as the Internet, and it canalso be stored on a computer-readable storage medium and distributed,for example. Various types of storage media can be used as this storagemedium, including flexible disks FDs, CD-ROMs, DVD-ROMs, magneto opticaldisks MOs, hard disks, and memories. It should be noted that informationstored on such storage media can be read by various types of readingdevices 1110.

FIG. 17 is an explanatory diagram showing a user interface of a printerdriver displayed on the screen of the display device 1104 connected tothe computer system. The user can use the input device 1108 to changethe various settings of the printer driver.

The user can select the print mode from this screen. For example, theuser can select as the print mode a quick print mode or a fine printmode. From this screen the user can also select the dot spacing(resolution) for printing. For example, from this screen the user canselect 720 dpi or 360 dpi as the print resolution.

Furthermore, the user can select the type of paper to print from thisscreen via the input device 1108. The main computer unit obtains theinformation about the type of paper from the input device 1108. Theinternal memory 1202 stores a table that associates the informationabout the type of paper and the information about the paper width. Basedon this table, the main computer unit can obtain information about thepaper width from the information about the type of paper. Thus, whenprinting, the main computer unit transmits information about the paperwidth to the printer. It should be noted that the table that associatesthe information about the type of paper and the information about thepaper width may be stored in the memory 65 of the printer. In this case,the main computer unit transmits information about the type of paper tothe printer, and the printer obtains, based on the table, theinformation about the paper width from the information about the type ofpaper that was received.

Furthermore, the user can instruct the printer to perform thecalibration operation from this screen via the input device 1108. Whenthe main computer unit receives an instruction to perform thecalibration operation from the input device 1108, it transmits acalibration command to the printer. Then, when the printer receives thecalibration command from the main computer unit, the printer performsthe calibration operation as described above. It should be noted thatalthough not shown in the diagram, buttons for instructing the printerto perform the calibration operation may be displayed on the screen.Thus, the calibration operation may be performed not only at the time ofshipment from a factory, but at any time desired by the user.

FIG. 18 is an explanatory diagram of a format of print data suppliedfrom the main computer unit 1102 to the printer 1106. The print data aregenerated from image information based on the settings of the printerdriver. The print data have a print condition command group and passcommand groups. The print condition command group includes a command forindicating the print resolution and a command for indicating the printdirection (single direction/bidirectional), for example. The printcommand group for each pass includes a target carry amount command CLand a pixel data command CP. The pixel data command CP includes pixeldata PD indicating the recording status for each pixel of the dotsrecorded in that pass. It should be noted that the various commandsshown in the diagram each have a header section and a data section;however, here they are shown simplified. Also, these command groups aresupplied intermittently command-by-command from the main computer unitside to the printer side. The print data are not limited to this format,however.

In the above description, an example was described in which the computersystem is constituted by connecting the printer 1106 to the maincomputer unit 1102, the display device 1104, the input device 1108, andthe reading device 1110; however, this is not a limitation. For example,the computer system can be made of the main computer unit 1102 and theprinter 1106, or the computer system does not have to be provided withone of the display device 1104, the input device 1108, and the readingdevice 1110. It is also possible, for example, for the printer 1106 tohave some of the functions or mechanisms of the main computer unit 1102,the display device 1104, the input device 1108, and the reading device1110. For example, the printer 1106 may be configured so as to have animage processing section for carrying out image processing, a displaysection for carrying out various types of displays, and a recordingmedia attachment/detachment section to and from which recording mediastoring image data captured by a digital camera or the like are insertedand taken out.

In the embodiment described above, it is also possible for the computerprogram for controlling the printer to be taken into the memory 65,which is a storage medium, of the control unit 60. The control unit 60may execute the computer program stored in the memory 65 so as toachieve the operations of the printer in the embodiment described above.

As an overall system, the computer system that is thus achieved issuperior to conventional systems.

===Other Embodiments===

The foregoing embodiment has been described focusing mainly on aprinter. However, it goes without saying that the foregoing alsoincludes the disclosure of printing apparatuses, printing methods,programs, storage media, computer systems, display screens, screendisplay methods, methods of manufacturing printed material, recordingapparatuses, and devices for ejecting liquids, for example.

Also, a printer, for example, serving as an embodiment was describedabove. However, the foregoing embodiment is for the purpose ofelucidating the present invention and is not to be interpreted aslimiting the present invention. The invention can of course be alteredand improved without departing from the gist thereof and includesequivalents. In particular, the embodiments mentioned below are alsoincluded in the invention.

<Regarding the Recording Apparatus>

In the embodiment described above, a printer was described as therecording apparatus. This is not a limitation, however. For example,technology like that of the present embodiment can also be adopted forvarious types of recording apparatuses that use inkjet technology,including color filter manufacturing devices, dyeing devices, fineprocessing devices, semiconductor manufacturing devices, surfaceprocessing devices, three-dimensional shape forming machines, liquidvaporizing devices, organic EL manufacturing devices (particularlymacromolecular EL manufacturing devices), display manufacturing devices,film formation devices, and DNA chip manufacturing devices. Also,methods therefor and manufacturing methods thereof are within the scopeof application. Even when the present technology is adopted in thesefields, the fact that liquid can be directly ejected (written) to atarget object allows a reduction in material, process steps, and costscompared to conventional cases to be achieved.

<Regarding the Ink>

Since the foregoing embodiment was an embodiment of a printer, a dye inkor a pigment ink was ejected from the nozzles. However, the liquid thatis ejected from the nozzles is not limited to such inks. For example, itis also possible to eject from the nozzles a liquid (including water)including metallic material, organic material (particularlymacromolecular material), magnetic material, conductive material, wiringmaterial, film-formation material, electronic ink, machining liquid, andgenetic solutions. A reduction in material, process steps, and costs canbe achieved if such liquids are directly ejected toward a target object.

<Regarding the Nozzles>

In the foregoing embodiment, ink was ejected using piezoelectricelements. However, the method for ejecting liquid is not limited tothis. Other methods, such as a method for generating bubbles in thenozzles through heat, may also be employed.

<(1) Regarding Storing of the Correction Value>

With the embodiment described above, the correction value detectedaccording to the calibration operation is the number of pulses (countvalue) of the pulse signal output from the encoder. However thecorrection value is not limited to this.

For example, the correction value may be a signal relating to theposition of the carriage for when the paper width sensor detected theedge of the paper. That is to say, provided that the correction valueexpresses the position of the edge of the paper, it may be in otherforms.

<(2) Regarding Storing of the Correction Value>

With the embodiment described above, the correction value detectedaccording to the calibration operation is stored in the memory 65 of thecontrol unit 60 of the printer. However, the location in which thecorrection value is stored is not limited to this. For example, thecorrection value detected according to the calibration operation may bestored in the memory of the main computer unit. In this case, theprinter first receives the calibration command and performs thecalibration operation, and then automatically transmits, to the maincomputer unit, the correction value that has been detected.

<Regarding the Blank Space>

In the foregoing embodiment, when printing on the paper, a blank spaceof 3 mm is formed on the left and right. That is to say, in theforegoing embodiment, the edge of the paper and the print start positionare separated by 3 mm. However the relative positional relationshipbetween the edge of the paper and the print start position is notlimited to this.

For example, it goes without saying that the width of the blank spacemay differ from 3 mm.

Furthermore, for example, the printing may also be printing performed onthe entire surface of the paper, that is, printing in which no blankspace is created, such as so-called borderless printing. Furthermore, ifborderless printing is performed, then the print start position may beoutside of the medium to be printed or on the position of the edge ofthe paper (the position at which the blank space becomes zero). In thisway, when performing so-called borderless printing, the print startposition can be provided at an appropriate position and also the timerequired for printing can be shortened.

INDUSTRIAL APPLICABILITY

With the printing apparatus of the present invention, it is possible toprovide the print start position at an appropriate position, as well asshorten the time required for printing.

1. A printing apparatus that forms a row of dots from a print startposition in a scanning direction to print on a medium to be printed,said apparatus comprising: a fixed guide; a movable guide that ismovable in said scanning direction; and a controller that causes asensor to detect an edge that is guided by said fixed guide, in saidscanning direction, of said medium to be printed, and that determinessaid print start position based on a result of detecting said edge ofanother medium to be printed without using a result of detecting theother edge that is guided by said movable guide.
 2. A printing apparatusaccording to claim 1, wherein said result of detecting said edge of saidother medium to be printed is stored; and wherein when printing on saidmedium to be printed, the stored detection result is read out, and saidprint start position is determined based on that detection result.
 3. Aprinting apparatus according to claim 1, wherein said sensor is providedon a carriage that is movable in said scanning direction.
 4. A printingapparatus according to claim 3, wherein said print start position isdetermined based on information about a position of said carriage forwhen said sensor detected said edge of said other medium to be printed.5. A printing apparatus according to claim 4, wherein said position ofsaid carriage is detected using an encoder.
 6. A printing apparatusaccording to claim 4, wherein said information about said position ofsaid carriage for when said sensor detected said edge of said othermedium to be printed is stored; wherein when printing on said medium tobe printed, said information about said position of said carriage thathas been stored is read out; and wherein said print start position isdetermined based on said information about said position of saidcarriage that has been read out.
 7. A printing apparatus according toclaim 1, wherein information about a relative positional relationshipbetween said edge of said medium to be printed and said print startposition is obtained; and wherein said print start position isdetermined based on this information and said result of detecting saidedge.
 8. A printing apparatus according to claim 7, wherein saidinformation about said relative positional relationship between saidedge of said medium to be printed and said print start position includesinformation about a blank space that is to be formed on said medium tobe printed.
 9. A printing apparatus according to claim 1, whereininformation about said medium to be printed is obtained; and whereinsaid print start position is determined based on said information aboutsaid medium to be printed and said result of detecting said edge.
 10. Aprinting apparatus according to claim 9, wherein said information aboutsaid medium to be printed includes information about a width of saidmedium to be printed.
 11. A printing apparatus according to claim 1,wherein printing is carried out on an entire surface of said medium tobe printed; and wherein said print start position is a position in saidscanning direction that is outside of or on the edge of the medium to beprinted.
 12. A printing apparatus that forms a row of dots from a printstart position in a scanning direction to print on a medium to beprinted, said apparatus comprising: a fixed guide; a movable guide thatis movable in said scanning direction; and a controller that causes asensor to detect an edge that is guided by said fixed guide, in saidscanning direction, of said medium to be printed; wherein said sensor isprovided on a carriage that is movable in said scanning direction;wherein a position of said carriage is detected using an encoder;wherein information about said position of said carriage for when saidedge of said other medium to be printed was detected is stored; whereinat least one of information about a width of said medium to be printedand information about a blank space that is to be formed on said mediumto be printed is obtained; wherein when printing on said medium to beprinted, said information about said position of said carriage is readout; wherein said print start position is determined based on saidinformation about said position of said carriage, and at least one ofsaid information about the width of said medium to be printed and saidinformation about the blank space that is to be formed on said medium tobe printed; and wherein said print start position is determined withoutusing a result of detecting the other edge that is guided by saidmovable guide.
 13. A computer-readable storage medium comprisinginstructions for causing a printing apparatus that forms a row of dotsfrom a print start position in a scanning direction to print on a mediumto be printed, to perform a method comprising: moving a movable guide insaid scanning direction; detecting an edge that is guidable by a fixedguide, in said scanning direction, of said medium to be printed; anddetermining said print start position based on a result of detectingsaid edge of another medium to be printed without using a result ofdetecting the other edge that is guided by said movable guide.
 14. Aprinting method for printing on a medium to be printed, said methodcomprising: a step of preparing a printing apparatus having a fixedguide, and a movable guide that is movable in a scanning direction; astep of detecting an edge, in said scanning direction, of another mediumto be printed, the edge being guided by said fixed guide; a step ofdetermining a print start position based on a result of detecting saidedge of said other medium to be printed; a step of ejecting inkdroplets, in said scanning direction, from the determined print startposition to print on a medium to be printed that is different from saidother medium to be printed; wherein said print start position isdetermined without using a result of detecting the other edge that isguided by said movable guide.